Method for establishing the proper working position of a doctor blade



June 7, 1966 J. T. COGHILL METHOD FOR ESTABLISHING THE PROPER WORKING POSITION OF A DOCTOR BLADE Filed Oct. 15, 1964 2 Sheets-Sheet 1 INVENTOR. JAMES T. COGHILL M MM ATTORNEYS BY W June 7, 1966 J. T. com-nu.

METHOD FOR ESTABLISHING THE PROPER WORKING POSITION OF A DOCTOR BLADE 2 Sheets-Sheet 2 Filed Oct. 13, L964 INVENTOR JAMES T. COGHILL ATTORNEYS United States Patent Office 3,255,038 Patented June 7, 1966 Ohio Filed Oct. 13, 1964, Ser. No. 403,592 3 Claims. (Cl. 117-120) This application is a continuation-impart of my copending United States application Serial No. 58,080, filed September 23, 1960, and assigned to the assignee of this application, now abandoned.

This invention relates to apparatus for coating paper and other web materials.

The invention is especially related to coating apparatus of the type which includes a backing roll, a coating device cooperating with the backing roll, and a flexible blade mounted downstream from the coating chamber which engages the surface of the backing roll during operation of the apparatus. For example, the invention may be used with coating apparatus of the type constructed in accordance with the copending apparatus application shown in U.S. Patent No. 3,079,887, issued March 5, 1964, to Robert 1. Jacobs and James T. Coghill, Serial No. 817,788, hereinafter designated as Case A, and assigned to the same assignee as this application.

It is a particular object of the present invention to provide a system and method for mounting the flexible blade in coating apparatus of the above type in accurately aligned position with the associated parts of the apparatus.

It is also an object of the invention to provide such a system and method which are also applicable to repositioning the flexible blade after it has been worn down through use.

It is particularly an object of the invention to provide such a system and method which assure the maximum degree of accurate alignment between the front edge of the blade and the backing roll during operation of the apparatus.

Additional objects and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims.

In the drawings FIG. 1 is a fragmentary view partly in side elevation and partly in vertical section illustrating the coating chamber and associated backing roll in coating apparatus in accordance with the invention;

FIG. 2 is a fragmentary view illustrating a preliminary step in mounting a blade in the apparatus of FIG. 1;

FIG. 3 is a side elevation view in section showing one of the gauge clips in accordance with the invention for mounting the flexible blade in position;

FIG. 4 is a fragmentary view showing parts of the apparatus of FIGS. 1-3 during initial mounting of the flexible blade in position;

FIG. 5 is a plan view of the apparatus shown in FIG. 3;

FIG. 6 is a section view taken along the line 66 of FIG. 3;

FIG. 7 is a view similar to FIG. 4 showing a subsequent stage in the practice of the invention;

FIG. 8 is a view similar to FIG. 7 showing the blade mounted in position and with the gauge clips removed; and 1 FIG. 9 is a fragmentary view partly in section and similar to FIG. 1 showing another embodiment of the invention.

Referring to the drawings, which illustrate preferred embodiments of the invention, FIG. 1 shows fragmentarily some of the parts of the coating apparatus in accordance with Case A, including the backing roll 10 and the coating chamber which is identified generally at 11 and includes a bottom plate 12. The coating chamber is mounted on a frame indicated generally at 13 for raising and lowering movement with respect to the roll 10 as described in Case A, and its front Wall is formed by a flexible doctor blade 15 which engages the surface of the roll 10 in the raised position of the coating chamber and frame 13.

The support structure for the blade 15 includes a plurality of hinges 20 which are mounted on the same frame 13 as the coating chamber by shaft means 21 and brackets 22, and these hinges are secured together by a common bar 23 so that they can swing in unison about the shaft means 21 between advanced and retracted positions with respect to the bottom plate 12 of the coating chamber. In the advanced position of the hinges 20 shown in full lines in FIG. 1, the back portion of the blade 15 is clamped against the edge of the plate 12 by an air pressure tube 25 (FIG. 7) which is supported in a holder bar 26 secured to each hinge 20 by a screw 27 arid washer 28. In the raised, operating position of the coating chamber, the front edge of the blade 15 is pressed yieldingly against the surface of the roll 10 by a second air pressure tube 30 which is supported by a holder bar 31 secured to each of the hinges 29 by a screw 33 and washer 34. Each of the hinges 20 includes a slot 35 which receives the screws 27 and 33 and also provides for vertical adjustment of these screws to establish the proper positions of the holder bars 26 and 31.

The present invention is particularly directed to establishing the blade 15 with its front edge in accurately positioned and aligned relation with the bottom plate 12 of the coating chamber and with the surface of the roll 10 in the operating position of the coating chamber. The several steps for accomplishing this rmult, and the means by which it is accomplished, are illustrated in detail in FIGS. 2-6.

. In setting upthe apparatus for operation with a new blade, the proper position of the coating chamber 11 should be established first, and this may be done as described in Case A. It is also necessary to establish the holder bar 31 in the proper position in the slots 35, which may be accomplished in a variety of ways. For example, a thin rule may be clamped in the position of the blade15 by the tube 25 and employed to check the position of the bar 31 along its entire length. Alternatively, a special gauge 37 may be used in the manner illustrated in FIG. 2, and this and the other operations described below are carried out with the coating chamber in its lowered position away from roll 10 as indicated in FIG. 7.

An important element in the practice of the invention is provided by the gauge clips 40 which are illustrated in detail in FIGS. 3 and 4. Each of these clips includes a U-shaped body 41 having the threaded stud 42 rigidly secured to and extending above and below the body 41. The rectangular slide plate 43 has slides adjacent the underside 44 of the body 41 and the slot 45 therein receives the stud 42 and the nut 46 is releasably attached thereto so that the slide plate 43 can be secured to the body 41. A clamp 47 is welded to the right hand end of the body 41 (FIG. 5) and extends thereabove so that v the lip 48 projects beyond the left hand end of the body 41. The upper stud 42 passes through an aperture in the top of the clamp 47 and the wing nut 49 threadedly engages the stud. so that the clamp 47 can be tightened against the bias of its natural resilience into rigid clamping engagement with the blade 15, as will be further explained. The left hand end of the slide plate 43 has a projection 51 deformed therefrom for aiding in the positioning of the clip 40 on the holder bar 31. The slide plate 43 is adjustable on the body 41 to provide accurately predetermined distances between the shoulder 52 on the body 41 and projection 51. The spacing of the projection 51 from the shoulder 52 of each clip 40 can be set at an accurately predetermined dimension so that when a plurality of these clips are mounted on the front edge of the blade 15 with the blade received and clamped by the lips 48, it is assured that these clips have their projections 51 tn accurately aligned and spaced relation with the front edge of the blade.. Satisfactory results have been obtained in the practice of the invention by utilizing blade clips 40 in sufficient number to space them approximately 18 inches apart along the edge of the blade 15 to be mounted in position.

The blade 15 with the clips 40 thereon is mounted while the coating chamber is in its lowered position away from the roll and with the hinges 20 swung to their retracted position as shown in FIG. 4 and in broken lines in FIG. 1. The several clips 40 are supported on the hinges 20 by engaging their projections 51 over the upper edge of the bar 31 as shown in FIG. 4. It will be seen that with the clips 40 of the construction described, their several projections 51 will all be accurately aligned, and this assures accurate positioning of the front edge of the blade with respect to the holder bar 31, which has already been adjusted to the proper relation with the coating chamber back plate 12. The thickness of the slide plate 43 is interposed between the bar 31 and the blade thus allowing the blade to be properly aligned in contact with the tubes 25 and 30.

The hinges are then swung to advanced position as shown in FIG. 7, and after the clips 40 have all been tapped to make certain that they are seating firmly on the bar 31, air pressure is applied to the tube 25, as by the means described in Case A. This step locks the back portion of the blade 15 to the bottom plate 12, and the clips 40 can then be removed by releasing their respective thumb screws 49. The resulting conditions are shown in FIG. 8, and the supporting structure is then ready to be raised to its operating position for use of the coating apparatus.

The system and mode of operation described for the initial positioning of the blade 15 can also be employed to re-position the blade after it has been worn down from use. It is merely necessary to lower the coating chamber, swing the hinges 20 to the retracted position shown in FIG. 4, and remove the blade. The clips 40 are then mounted on the blade in the same manner as described in connection with a new blade, and the same procedure is then followed to mount the blade, clamp it in operative position, and remove the clips.

Another embodiment of the invention is shown in FIG. 9, wherein the mechanism used to secure the blade 15 against the base member 60 is slightly difierent from that shown and described in FIG. 1, e.g. a fountain type coater wherein a coating chamber as discussed in Case A is not used. In'particular, the clamping structure 61 pivots on a plurality of hinges 62 about the pins 63 between a position wherein the blade is clamped against the base member and an alternate position spaced therefrom. The elongated hinge'bar 65 is secured to the hinges 62 and extends across the machine coextensive with the blade 15. The blade 15 is clamped against the base member 60 by the inflatable tube 66 mounted in a groove in the hinge bar 65 in a manner similar to that described above.

The mechanism for applying adjustable pressure to the 4 flexible blade 15 includes the profiling blade 68 which is in direct contact with this blade 15 and which is deformed along the length thereof by rotating the screws 70 which move a plurality of L-shaped plates 71 against the bias of the springs 72 toward and away from the profiling blade 68. This L-shaped plate 71 has an upstanding dog 73 therein which abuts the profiling blade to impart movement of the plate 71 thereto. The resilience of the profiling blade 68 causes it to resume its position when the dog is backed off, and the cover 65 extends across the top of the L-shaped plate 71 and is held in position by the retainer 76.

The clamp 40a is substantially identical to that described above, and therefore the similar components are identified by the same reference characters. The essential difference between the clamps 40 and 40a is that the latter does not have the projection 51 on the slide plate 43a since the forward edge 77 of the slide plate 43a abuts the profiling blade 68 to deform locally the doctor blade with respect to the clamping structure. In all other respects this embodiment operates in substantially the same manner as that described above to position accurately the doctor blade 15 in position with respect to the backing roll 10.

While the method and form of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to this precise method and form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. In a method of establishing the precise proper working position of a flexible doctor blade adapted to move between an operative position for cooperation with a backing roll and a retracted position spaced from said backing roll, said doctor blade being held by supporting structure having holding means movable between a released position and an advanced position wherein the back edge portion of the blade is clamped against a support plate, the steps of moving said support structure to said retracted position, manually adjusting the relative position of a blade abutting shoulder on a series of individual gauge clips to a preset position correlated with the precise position into which the blade is to be positioned, rigidly clamping said series of individual gauge clips along the front edge of said blade and distributed along the entire length thereof with the front edge of said blade in contact with said abutting shoulders of said gauge clipsso that said gauge clips will not move relative to the blade during handling and set up, placing the gauge clips while attached to said blade at preselected locations on the supporting structure to locate the front edge of the blade in aligned relation with said supporting structure while said supporting structure is in said released position, moving said supporting structure to said advanced position to clamp the back portion of the blade against said support plate to position said front edge of said blade in aligned relation with said backing roll, then removing said gauge clips, and thereafter moving said support structure to said operative position with said backing roll to position the front edge of the blade in precise working position with respect to the backing roll without further adjustment of the gauge clips or the blade.

2. In a method as defined in claim 1 the step of coating the surface to be doctored by said flexible doctor blade by passing the surface to be coated through a coating chamber mounted on said support structure.

3. In a method as defined in claim 1 the step of clamping said back edge portion of said blade to said support structure of inflating expandable tube means which extends along the length of said blade.

(References on following page) References Cited by the Examiner 3,017,828 1/1962 Beh nger 101-157 UNITED STATES PATENTS 3,026,842 3/1962 Faeber 118413 X 12/1896 Younger 24-243 FOREIGN PATENTS 9/1906 Reams 24 243 5 596,472 1/1948 Great Britain.

3/1937 Fritsche- MURRAY KATZ, Primary Examiner.

Z132? fiigo ijjiijjjj 112323; RICHARDDNEVIW 1 12/1959 Smith 15 256'5 J. P. MCINTOSH, Assistant Examiner. 

1. IN A METHOD OF ESTABLISHING THE PRECISE PROPER WORK ING POSITION OF A FLEXIBLE DOCTOR BLADE ADAPTED TO MOVE BETWEEN AN OPERATIVE POSITION FOR COOPERATION WITH A BACKING ROLL AND A RETRACTED POSITION SPACED FROM SAID BACKING ROLL, SAID DOCTOR BLADE BEING HELD BY SUPPORTING STRUCTURE HAVING HOLDING MEANS MOVABLE BETWEEN A RELEASED POSITION AND AN ADVANCED POSITION WHEREIN THE BACK EDGE PORTION OF THE BLADE IS CLAMPED AGAINST A SUPPORT PLATE, THE STEPS OF MOVING SAID SUPPORT STRUCTURE TO SAID RETRACTED POSITION, MANUALLY ADJUSTING THE RELATIVE POSITION OF A BLADE ABUTTING SHOULDER ON A SERIES OF INDIVIDUAL GAUGE CLIPS TO A PRESET POSITION CORRELATED WITH THE PRECISE POSITION INTO WHICH THE BLADE IS TO BE POSITIONED, RIGIDLY CLAMPING SAID SERIES OF INDIVIDUAL GAUGE CLIPS ALONG THE FRONT EDGE OF SAID BLADE AND DISTRIBUTED ALONG THE ENTIRE LENGTH THEREOF WITH THE FRONT EDGE OF SAID BLADE IN CONTACT WITH SAID ABUTTING SHOULDERS OF SAID GAUGE CLIPS SO THAT SAID GAUGE CLIPS WILL NOT MOVE RELATIVE TO THE BLADE DURING HANDLING AND SET UP, PLACING THE GAUGE CLIPS WHILE ATTACHED TO SAID BLADE AT PRESELECTED LOCATIONS ON THE SUPPORTING STRUCTURE TO LOCATE THE FRONT EDGE OF THE BLADE IN ALIGNED RELATION WITH SAID SUPPORTING STRUCTURE WHILE SAID SUPPORTING STRUCTURE IS IN SAID RELEASED POSITION, MOVING SAID SUPPORTING STRUCTURE TO SAID ADVANCED POSITION TO CLAMP THE BACK PORTION OF THE BLADE AGAINST SAID SUPPORT PLATE TO POSITION SAID FRONT EDGE OF SAID BLADE IN ALIGNED RELATION WITH SAID BACKING ROLL, THEN REMOVING SAID GAUGE CLIPS, AND THEREAFTER MOVING SAID SUPPORT STRUCTURE TO SAID OPERATIVE POSITION WITH SAID BACKING ROLL TO POSITION THE FRONT EDGE OF THE BLADE IN PRECISE WORKING POSITION WITH RESPECT TO THE BACKING ROLL WITHOUT FURTHER ADJUSTMENT OF THE GAUGE CLIPS OR THE BLADE.
 2. IN A METHOD AS DEFINED IN CLAIM 1 THE STEP OF COATING THE SURFACE TO BE DOCTORED BY SAID FLEXIBLE DOCTOR BLADE BY PASSING THE SURFACE TO BE COATED THROUGH A COATING CHAMBER MOUNTED ON SAID SUPPORT STRUCTURE. 